The present invention relates generally to vehicular transmissions. More particularly, the present invention relates to the operation of vehicular accessory units that are, by virtue of the subject invention, capable of receiving input power from an engine as well as a source of stored electrical energyxe2x80x94either selectively or in combination. Specifically, therefore, the present invention relates to an electro-mechanical interface in the nature of a series hybrid power unit that directs the operating power between the input power sources and the various vehicular accessories.
The purpose of a vehicular transmission is to provide a neutral, at least one reverse and one or more forward driving ranges that impart power from an internal combustion engine, and/or other power sources, by which to drive the members that deliver the tractive effort from the vehicle to the terrain over which the vehicle is being driven.
Irrespective of the operative structure of a vehicular transmission per se, some provision is employed for powering accessory units that are required, or desired, for the most effective operation of the vehicle. In a typical prior art series hybrid drive system, as represented by what is currently being used by large metropolitan transit systems, there are four main electrical power conversion systemsxe2x80x94i.e.:
1) A main propulsion system that employs an inverter to convert DC electrical power provided by a battery, or the like, to AC electrical power for operating an AC traction drive motor;
2) An auxiliary power unit (generally designated as the APU) that includes an engine, a generator and an inverter;
3) An accessory drive system incorporating an accessory DC to AC inverter to change the DC electrical power provided by one or more batteries, or the like, into AC power in order to drive a plurality of AC drive motors, one drive motor to power each of the vehicle accessories such as the coolant pumps, cooling fans, an air compressor, battery fans, a power steering pump, etc., and;
4) A DC to DC step-down converter to receive DC power from a battery pack, or the like, and provide the proper DC voltage to charge 12 and 24 volt batteries used in the operation of one or more accessories available to the vehicle.
Such series hybrid drive systems also typically utilize four main modes of operationxe2x80x94i.e.:
1) Pure electrical propulsion;
2) Hybrid propulsion;
3) Regenerative braking; and,
4) Charging
It is, therefore, one primary aspect of the present invention to provide a new and novel system to power vehicular accessory units.
It is another aspect of the present invention provide a new and novel system, as above, that employs an electro-mechanical interface between the accessories and the source, or sources, of power by which the accessories are operated.
It is a further aspect of the present invention to provide new and novel system, as above, that utilizes only two electrical power conversion systemsxe2x80x94i.e.: 1) a main propulsion system employing a source of DC electrical power and an AC traction drive motor; and, 2) an auxiliary power unit employing an engine, a motor/generator and the electro-mechanical interface that serves as an accessory drive transfer mechanism.
It is a still further aspect of the present invention to provide new and novel system, as above, wherein the electro-mechanical interface incorporates two separate power output mechanisms (one that may be identified as a xe2x80x9cdirect drivenxe2x80x9d mechanism and another that may be identified as a xe2x80x9cclutch drivenxe2x80x9d mechanism).
It is an even further aspect of the present invention to provide new and novel system, as above, that will operate not only the accessories available in the prior art systems but also additional accessories in the nature of a scavenge pump, an air conditioning compressor and a 12/24 volt generator.
These and other aspects of the invention, as well as the advantages thereof over existing and prior art forms, which will be apparent in view of the following detailed specification, are accomplished by means hereinafter described and claimed.
By way of a general introductory description, an electro-mechanical interface for driving accessory loads according to the present invention employs at least a first tier of geared output shafts rotatably supported within a frame and meshingly engaged in a daisy-chain configuration having first and second ends. One end of the first tier of geared output shafts in the daisy-chain configuration meshingly engages a first, geared transfer shaft. The first, geared transfer shaft connects to an internal combustion engine through a releasable, or xe2x80x9cdisconnectxe2x80x9d clutch means. The other end of the aforesaid first tier of geared output shafts in the daisy-chain configuration meshingly engages a second geared transfer shaft that is permanently connected to a motor/generator. The geared output shafts in the aforesaid daisy-chain configuration are available to drive auxiliary loads.
A second tier of geared output shafts are also rotatably supported within the aforesaid frame. The geared output shafts in the second tier meshingly engage, also in a daisy-chain configuration having first and second ends. One end of the daisy-chain defined by the second tier of geared output shafts meshingly engages a geared linking shaft, and the geared linking shaft selectively connects to the first geared transfer shaft in the first tier of geared output shafts through a selectively engageable clutch means. The geared output shafts in the second tier of output shafts are also available to drive auxiliary loads.
As such, powering the specific accessories shown and described herein are only illustrative, and as will become apparent to those skilled in these arts can be modified in numerous ways within the scope and spirit of the invention; the invention being measured by the appended claims and not by the details of the specification.